The present invention relates to a milking plant of the kind operating with at least two different vacuum levels.
In milking plants of this kind, vacuum is usually provided by a vacuum pump which produces a high vacuum, and a reduction valve which reduces the vacuum level to a suitable low vacuum when required. The drawback of this arrangement is that a relatively large vacuum pump is required since the pump constantly works against high vacuum and the capacity of a vacuum pump is reduced with increasing vacuum. This results in a relatively large energy consumption and also a high operating temperature of the vacuum pump.
It is also known to provide the plant with two separate vacuum systems, one for high vacuum and one for low vacuum, each being provided with a vacuum pump. In this case no reduction valve is required since the vacuum pumps directly deliver vacuum of the respective desired level. However, the arrangement will be relatively expensive since two vacuum pumps with appurtenant motors are required.